Signal.



R. M. GILSON.

. SIGNAL.

AFPUCAUON FILED JAN. I8, 1911. LPQWQW@ 1 Patented May 29, 1917.

INVENTOR.

HIS ATTORNEY IN FACT FFMC.;

ROBERT M. GIISON, OF PITTSBURGH, -PENNSYLVANI SSIGNOR T0 THE 'UNION STCE .& SIGNL COMPANY, 0F SWISSVAIE, PENNSYLVANIA, A CORPORATION F PSYLVNIA.

SIG-NAL.

specmmion of Letters Patent.

Patented May 29,1911?.

Original application med January 20, 1914, Serial No. 813,157. Divided and this application tiled January v Y la, 1917. Serial No. 143,091.

' To all whom t may concern.'

Be it known that I, ROBERT M. GnisoN, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Signals, of Vwhich the following is a specification.

My invention relates to signals and particularly to signals of the type in which a source of light is employed for giving indications both at night and in daylight. Signals embodying my invention are particularly adapted for use in railway signaling, although they are not limited to this particular adaptation. When a signal of the type mentioned is used on a railway curve, the beam of light projected by the signal should be visible over all points on the curve in the rear of the signal. Hence, this beam is preferably elongated in a horizontal direction, but not in 'a vertical direction. Furthermore, it is desirable that the beam should appear to be about of the same intensity from all oints on the curve, hence the beam refera ly varies progressively in intensity rom a maximum value adjacent one end to a minimum value adjacent the other, the more intense portion of the light being directed toward the end of the curve farthest from the signal and the less intense portions being directed toward the sections of the curve nearer to the signal. One feature of my invention is the provision of a si al which will project an elongated beam o light which varies progressively in intensity from the maximum value adjacent one end to a minimum value adjacent the other.

rlhe present application is a division of my copending application iled January 20, 1914, Serial No. 813,157, for signals.

1 will describe one form of signal embodying my invention, and will then point out the novel features thereof in claims.

1n the accompanying drawings, Figure 1 is a top view showing one form of signal embodying my invention. Fig. 2 is a view on an enlarged scale showing in detail one set of dimensions which may he employed for each of the prismatic corrugations -14 of the screen 12 shown in Fig. 1, to obtain a certain degree of elongation of the beam projected thereby, and to cause variation of the .which are directed the several parts of the beam' indicated by the zones in Fig. 3.

Similar reference characters refer to similarparts in each of the several views.

Referring first to Fig. 1, the signal here shown comprises an incandescent lamp 10 from which a beam of light comprising substantially parallel rays 13 is projected by a lens 11. Although l have shown an incandescent lamp as the source of light, itis understood that any other suitable source may be employed; and although 1 have shown a lens, it is understood that any other suitable means may be employed for projecting ,a beam of substantially parallel rays from the source 10.

Located in the path of the beam 13 is a glass screen 12 which is adapted to elongate the beam horizontally, and to cause its intensity to vary progressively from a comparatively high Value adjacent one end to a comparatively low value adjacent the other. As here shown, this screen comprises a plurality of vertically disposed parallel prismatic oorrugations 14, which corrugations l will hereinafter refer toas prisms. The inclined face of each prism is concaved substantially as shown, so that the angle of refraction varies by small increments from a minimum value adjacent one edge of the prism to a maximum value adjacent the other edgefr This variation is illustrated by the lines 15, which indicate the directions of the rays emerging from the various parts of the prism. It will be seen'that the 'beam projected from each prism is therefore elongated along the line Ill-Ill. Each prism is furthermore designed so that the intensity of the beam emerging therefrom varies from a maximum value adjacent the edge having the smallest angle of refraction to a minimum value adjacent the edge having the greatest angle of refraction, so that the variation of intensity, along the line 111-111, of the beam from each prism is substantially as indicated by the curve' in Fig. 3. lnasmuch .as all of the prisms 14 are alike, the

Sii

curve in Fig. 3 also indicates the variation in intensity along the line III-III of the beam emerging from the signal as a whole.v

In Fig. 2 I have shown in detail one of the prisms 14, together with the exact dimensions which may be employed to give a spread oit' approximately 150 and to cause the variation of intensity indicated by the curve in Fig. 3. It will be seen that the rays l5 from each prism intermingle with those from the other prisms, resulting in a smooth curve of variation of intensity 'such as that shown in Fig. 3.

In Fig. 4 I have shown a railway curve F, at one end of which is a signal S, such as is shown in Fig. 1, and which projects a horizontally elongated beam varying in intensity substantially as indicated by Fig. 3. Signal S is so located that the portion A of the beam projected by the signal is directed toward section A of the curve, portion B toward B, etc. rI`hat is, the

most intense portion of the beam is directed toward the section of the curve farthest from the signal, and the portions of the beam of progressively decreasing intensity are directed toward the sections of the curve progressively approaching the signal.

Hence, as an observer passes along the curve F toward the signal, the beam of light is constantly visible, and constantly appears of substantially the sameintensity. There is, therefore, no light wasted in unnecessarily intense ilumination at any one part of the curve.-

Although I have herein shown only one form. of signals embodying my invention, it is understood that various changes and modifications maybe made therein Within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is means for projecting from said Source a beam of substantially parallel rays, and a glass screen located in said beam and comprising a series of .vertically disposed prisms, the angle of refraction of each of which prisms increases progressively from a minimum value adjacent one side of the prism to a maximum value adjacent the other, said beam-projecting means and said .screen beingso placed that the portions of the beam which are deflected through the of the curve and the portions of the beam which are deflected through the least angle are directed toward the other end of the curve.

2. A signal adapted for use on a railway curve and comprising a source of light, means lfor projecting from said source a beam of substantially parallel rays, and a glass screen located in said beam and comprising a series of vertically disposed prisms, the angle of refraction of each of which prisms increases progressively from a minimum value adjacent one side of the prism to a maximum value adjacent the other, and the intensity of the beam emerging from each 'prism varying progressively from a maximum value adjacent one side to a minimum value adjacent the other side, said beam projecting means and said screen bei-ng so located that the portion of the beam having the highest intensity is directed toward the far end of the .curve and the portion of the beam having the lowest intensity is directed toward the part of the curve nearest to the signal.

3. A signal comprising a source of light, mea-ns for projecting from said source a beam of substantially parallel rays, and a glass screen located in said beam and comprising a series of vertically disposedprisms the angle of refraction of each of which prisms increases progressively from' a minimum value adjacent one side of the prism to a maximum value adjacent the other side.

4. A signal comprising-a source of light, means for projecting from said source a beam of substantially parallel rays and a glass screen located in said beam and comprising a series of vertically disposed prisms the angle of refraction of each of which prisms increases progressively from a minimum value adjacent one side of the prism to a maximum value adjacent the other side, and the intensity of .the beam emerging from each prism varying progressively from a maximum value adjacent one side to a minimum value adjacent the other side.

In testimony whereof I aiix my signature in presence of two witnesses.

ROBERT M. GILSQN. Witnesses:

A. HERMAN WEGNER, W. P. IhIoLBEN. 

